[nmrtist]

Summary

Add traceable chemical-shift references so 3D spectra and assigned peaks use consistent corrected coordinates across processing, export and project persistence.

• Record absolute acquisition-axis offsets, reference sources and manual confirmation.
• Preserve peak IDs and assignments through reference edits, phase processing and Undo/Redo; update viewports and invalidate affected cursor readings.
• Compare confirmed single-atom observations within the same sample conditions using indexed matching that preserves every observation pair.
• Identify reference draft targets when switching spectra, add interaction and persistence regressions, and update both language guides.

Validation

• cargo pr-check — passed in 145 seconds, including reference Undo/Redo, project roundtrips, observation matching and spectrum-switch interaction tests. Ran with the Windows permissions required by ACL and discovery-lock tests.
• npm run build in docs/ — passed, generating 123 pages.
• git diff --cached --check — passed.

UI display logic

• Reference controls are panel-local widget interactions, exempt from command catalog registration.
• Draft target differences and stale-state errors provide explicit guidance.
• No layout changes from background events; panels are never auto-closed.
• Docs updated in docs/ (English and zh-CN) for user-visible behavior.